1. Field of the Invention
This invention relates to novel catalysts for olefin polymerization. More particularly, it is concerned with a process for polymerizing olefins which comprises polymerizing or copolymerizing olefins in the presence of a catalyst which is composed of a solid substance obtained by copulverizing (1) magnesium halide and/or manganese halide, (2) an organic halide compound, (3) a chain or cyclic silicone compound with the recurring structural unit represented by the general formula ##STR2## wherein R' and R" respectively represent a hydrogen, alkyl, aryl, alkoxy or hydroxy group, and (4) a titanium compound, said solid substance being combined with an organometal compound, thereby greatly increasing the polymer yield per solid as well as the polymer yield per transition metal and also very efficiently yielding polymers of high bulk density and good particle features thus excluding the need for a residual catalyst-removing step.
2. Description of the Prior Art
The prior art has utilized catalyst comprising a transition metal compound such as titanium compounds carried on magnesium halide which are known by Japanese patent publication No. 12105/1964, and other catalysts comprising copulverized magnesium halide and titanium tetrachloride which are known by Belgian Pat. No. 742,112.
However, as it is desirable from the polyolefin-production point of view that the polymerization activity be as high as possible and from the productivity point of view that the bulk density of the polymer product be as high as possible, the process according to the aforementioned Japanese patent publication is not satisfactory in that the bulk density of the polymer product as well as the polymerization activity are low. The process disclosed in Belgian Pat. No. 742,112 needs improvement in that, although the polymerization activity is high, the bulk density of the polymer product is low. In addition, whereas it is desirable from the polymer slurry-handling point of view as well as from the polymer particle-handling point of view that the polymer particles contain as little as possible of fine particles, for example, of a size of 100.mu. or smaller and coarse particles, for example, of a size of 1000.mu. or larger, the process of Belgian Pat. No. 742,112 needs improvement in that the catalysts contain a large portion of fine particles. We have previously proposed that polymers of high bulk density can be obtained by combining a solid obtained by copulverizing magnesium halide and/or manganese halide, an organic halide compound, and a titanium compound with an organoaluminum compound and/or an organozinc compound (Japanese patent public disclosure No. 42584/1977). Further improvement has been desired from the slurry-handling point of view for the above process in that coarse particles may be formed.